This invention relates generally to a process and apparatus for making absorbent members such as an absorbent core used for articles such as disposable diapers, children's training pants, feminine care articles, incontinence articles and the like, and more particularly to such an absorbent member which is constructed of a fibrous material and has a reinforcing web incorporated therein.
One common method of forming fibrous absorbent members employs conventional air forming techniques in which a fibrous sheet of cellulosic or other suitable absorbent material is fiberized in a conventional fiberizer or other shredding or comminuting device to form a fluidized flow of discrete fibers. Particles of superabsorbent material may also be mixed with the discrete fibers. The mixture of fibers and superabsorbent particles are entrained in an air stream within a forming chamber and directed by the air stream to a foraminous forming surface that moves within the forming chamber. The air passes through the forming surface while the fibers and superabsorbent particles are collected on the forming surface to form a fibrous absorbent member. In addition, bonding agents or other strengthening components may be incorporated to provide a stabilized absorbent member. The absorbent member may then be stored or immediately directed for further processing and assembly with other components to produce an absorbent article.
Other conventional techniques, such as dry-forming techniques, wet-laying techniques, foam-forming techniques, and various wet-forming techniques, have also been employed to form stabilized absorbent members. The resulting absorbent members have included absorbent fibers, natural fibers, synthetic fibers, superabsorbent materials, binders, and strengthening components in desired combinations.
Absorbent members may also be strengthened by adding reinforcing materials, such as reinforcement filaments, tissue layers, fabric layers and netting materials to the fibrous material. For example, co-assigned U.S. patent application Ser. No. 10/306,086 entitled “Absorbent Article with Reinforced Absorbent Structure,” filed Nov. 27, 2002 by David W. Heyn et al., the entire disclosure of which is incorporated herein by reference, discloses a reinforced fibrous absorbent member comprised of a fibrous material and a scrim (e.g., netting or mesh material) incorporated within the fibrous material to strengthen the absorbent member and reduce the risk of cracking thereof during use.
European Patent Application EP 0467409 A1 also discloses an absorbent pad having a reinforcing web therein. The reinforcing web comprises longitudinally and laterally intersecting strands. Some or all of the strands are formed of an inner first polymeric material having a first melting point and an outer second polymeric material having a second melting point lower than the first melting point. The reinforcing web is introduced into a forming chamber containing fluidized fibrous material which is deposited on a drum. The openings defined by the intersecting strands of the web are sized sufficiently large to permit the fibrous material to pass through the web to a forming surface to form a first layer of the pad. The web is then laid on the first pad layer and a second layer is formed over the web. The entire pad is then heated to melt the second, but not the first, polymeric material of the web strands to fuse the web between the first and second layers of the absorbent pad.
However, a suitable process and apparatus for forming a reinforced fibrous absorbent member without the need for bonding or otherwise adhesively securing a reinforcing web within the absorbent member has heretofore been unknown. In particular, there is a need for a process and apparatus which delivers a continuous web of scrim into an air forming apparatus in a manner that facilitates proper alignment and securement of the scrim within the fibrous absorbent member to inhibit separation of the fibrous material from the scrim.